AK Steel (NYSE: AKS) said that the United States Court of Appeals for the Federal Circuit denied, on March 20, 2013, ArcelorMittal's (NYSE: MT) petition for re-hearing in its patent infringement lawsuit involving aluminized boron steel.

This week's court decision again confirms that AK Steel does not infringe the patent and can sell its ULTRALUME® aluminized boron steel product. AK Steel's ULTRALUME® product is utilized for hot-stamped, press-hardened applications where the ultimate tensile strength is less than 1,500 MPa.

AK Steel's ULTRALUME® is an advanced high-strength steel that is growing in popularity for various automotive applications. AK Steel said that ULTRALUME® has been accepted for use by numerous automotive original equipment manufacturers (OEMs).

AK SteelAK Steel produces flat-rolled carbon, stainless and electrical steels, primarily for automotive, infrastructure and manufacturing, construction and electrical power generation and distribution markets. The company employs about 6,100 men and women in Middletown, Mansfield, Coshocton and Zanesville, Ohio; Butler, Pennsylvania; Ashland, Kentucky; Rockport, Indiana; and its corporate headquarters in West Chester, Ohio. Additional information about AK Steel is available on the company's web site at www.aksteel.com.